High ISO's

99% of the time I use a tripod, everytime I go out my tripod goes with me and is now an essential part of my photographic kit.
But every now and then your tripod will be at home as it won't be feasible to take it everywhere so sometimes you will be forced to push up the ISO of your camera to get a shutter speed fast enough to handhold in low light conditions.
When you increase the ISO of your camera you are essentially making your sensor more sensitive to light which means you can get faster shutter speeds.
The reason I use my tripod so much is to use a low ISO of around 200 which gives me high quality crisp images but when you start pushing up your ISO the images start suffering from noise.
How high you push your ISO all depends on the abilities of your camera and how well it controls noise.
I use a Nikon D300s which is an amazing camera but is getting a little long in the tooth so I dread pushing up the ISO above 800 as the noise in the pictures is quite evident.
Some of the newer cameras have advanced so much technologically that the ISO can be pushed up to and beyond 6400 with very little noise whilst keeping amazing quality.
Recently I took my camera to work which I kept in my work bag ready to pull out if a shot arose, due to the nature of my job (train driver) I couldn't take my tripod with me as they can be very big and cumbersome and also weigh lots too.
On this particular day I arrived at London bridge train station and saw a picture opportunity of the station with the new Shard building behind all lit up.

I am really pleased with this picture which was only possible to capture handheld thanks to a few factors.
  • A wide aperture of f/3.5
  • Vibration Reduction built into my Nikon 16-85 lens
  • An increased ISO of 1600
The exposure of this picture was 1/13 sec and was only possible thanks to the points above and a very steady hand.
Without these the image would have probably been blurred, shaky and unusable.
The big downfall with using a high ISO in this case 1600 on my Nikon D300s the noise is quite severe.


The left image is the unprocessed image and the right image is the processed image.
The unprocessed image has been brightened up a little to show you the extent of the noise in the picture.

Below is a crop of both images.


 The left image is the unprocessed picture cropped in and the right image is the processed image cropped in.
So even though the noise is very severe to begin with thanks to the high ISO processing can help correct this to a certain extent.
For the processed image I selected the sky only and used Noise Ninja a noise reduction software to reduce the the noise.
Noise Ninja did a great job but the extremity of the noise was so severe in the sky that I had to take matters further and use software blurring to rescue my picture.
With the sky still selected I first used lens blur but this gave a very bad halo and glow around the edges, I then tried motion blur which had much better results.
The motion blur essentially softened the sky enough to get rid of the grain or noise and being motion blur it gave the impression the clouds were moving.

Conclusion
Even though I am an advocate of using your tripod it's not always possible so high ISO's have their place and can do an amazing job if used correctly in camera and with post processing.
With newer cameras the higher ISO's quality will be so good that no processing or virtually no processing will be needed to improve the image but for now until I can afford to upgrade to a Nikon D800 I will be keeping my ISO under 800 and dabbling in post processing to get the quality I need.

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